4. Positive Prone Instability Test: The participant will lie on his/her stomach with the legs off the edge of the table and the feet resting on the floor. The examiner will apply a posterior-to-anterior pressure at each spinous process (T12-S1). Any provocation of pain will require the participant to lift their legs off the floor while the pressure is reapplied to the painful level. If the pain subsides with elevation of the legs, this is considered a positive test.